Which enzyme is essential for nitrogen fixation and requires iron and molybdenum for its activity?

Nitrogenase is the enzyme that plays a crucial role in nitrogen fixation, a process where atmospheric nitrogen (N₂) is converted into ammonia (NH₃), which can then be utilized by living organisms. This enzyme is found in certain bacteria and archaea, particularly those that have symbiotic relationships with plants, such as legumes.

For nitrogenase to function effectively, it requires the presence of specific metal cofactors, namely iron and molybdenum. Iron is a key component in the structure of the enzyme, while molybdenum is integral to the enzymatic activity necessary for the reduction of nitrogen gas.

Understanding the role of nitrogenase is essential in fields such as agriculture and ecology since this process forms the basis for the nitrogen cycle, which is fundamental for soil fertility and plant growth. Other enzymes listed, such as ribulose bisphosphate carboxylase, amylase, and protease, have different functions related to photosynthesis, carbohydrate digestion, and protein breakdown, respectively, and do not participate in nitrogen fixation.